Return bend for cracking stills



Feb. 11, 1936. c. E. ARD

RETURN. BEND FOR CRACKING STILLS Filed Jan. 25 1953 2 Sheets-Sheet l Feb. 1 1, 1936. Q E, ARD

' RETURN BEND FOR CRACKING STILLS Filed Jan. 25, 1933 2 Sheets-Sheet 2 INVENTORiU 144/ Patented Feb. '11, 1936 UNITED STATES PATENT OFFICE- RETURN BEND FOR CRACKING STILLS Charles E. Ard, Birmingham, Ala., assignor to Fred C. Fantz, Webster Groves, Mo.

My invention relates 'to that class of return bends in which the return bend is held in engagement .with the ends of the still tubes by means of toggles mounted in the upper part of the walls of the housing in which the return bend itself is mounted. These toggles carry set screws. the inner ends of which engage abutments formed on the housing on the return bend, so that by tightening them, the face of the return bend and the ends of the tubes are drawn into a tightjoint.

More particularly, my invention relates to that class of devices in which the tubes are demountably mounted in the housing so that it is possible to remove a defective tube without having to de- 15 stroy the adjacent good tube. It is also possible to remove the tubes for inspection or replacement and it is also possible to remove them to a less hazardous portion of the still so as to lengthen the life of the equipment materially in 20 this manner.

It is well known that the refining companies are being forced to higher temperatures and higher pressures in the cracking of gasoline by reason of the automotive engineers requiring so- 25 called anti-knock gasoline. The results of these higher temperatures and pressures is that there is a decided tendency in'the industry to get away from any threaded parts or any additional loose parts such for example as the threaded plugs in 30 the standard header box or return bend. The

higher pressure and temperature is liable to produce an excess warping of the tubes which is present in all stills. As a consequence unless some means are provided to hold the ends of the 3-3 tubes firmly in place when the return or U bend is removed it is nearly, if not quite, impossible to obtain a tight joint.

The industry has turned to the applicant's U bend to get away from the necessity of using the threaded plugs referred to above, and these return bends areusually held to their seats by means of toggles mounted in the side walls of the housing. These toggles have to be removed before the U bend can be removed and then re- 45 placed when the U bend is put back.

' My invention has for its principal object to do away with the detachable toggles mounted in the side walls of the housing adjacent their upper end. w

5 A further object of my invention is to provide a construction in which the entire housing is made in one integral piece from which the tubes or a tube can be removed if desired for inspection or replacement.

55 My means of accomplishing the foregoing objects may be more readily understood by having reference to the accompanying drawings which are hereunto annexed and made a part hereof, in which I Fig. l is a side elevation of my improved re- 5 turn bend, one-half being shown in section;

Fig. 2 is a top or plan view of the same;

Fig. 3 is an 'end elevation; and

Fig. 4 is a section on theline 4-4 in Fig. 1.

Similar reference numerals refer to similar parts throughout the entire description.

As shown in the drawings-I have illustrated only a fragmentary portion of a pair of tubes I and 2 which are connected by a conventional U or return bend 3 which provides a passageway therethrough so as to permit the liquid in the tubes to flow uninterruptedly from one to the other. In the drawings I have illustrated a circumferential groove formed in the faces of the return bend which groove is adapted to engage the convex ends. of, the tubes, this type of joint having been found highly satisfactory in practice, but it will be recognized that my invention is not confined to any particular type of joint nor do I desire to be understood as limiting myself to the specific form disclosed in the drawings.

The return bend 3 is mounted in a. hous preferably cast or formed integral. Although I may cast, it may be found desirable to forge the housing and weld it together. This housing comprises annular portions 4 and 5 each of which is provided with a pair of upwardly extending side walls 6 and I. These walls are joined at the top by a connecting wall 8 in'which is mounted set screws 9. These walls should be spaced to permit the insertion of'the return bend as shown in dotted lines in Fig. 1. The inner ends Ill of the set screws 9 engage abutments ll formed on the external wall of the return bend 3. As illustrated the ends of the tubes are upset forming shoulders 40 I2, which abut shoulders formed on sectional metal bushings l3 which are mountedintermediate the external walls of the tubes and the internal walls of the annular portions 4 and 5. The device is assembled in the following manner: 40 The annular members arepassed over the ends of the tubes until they project into the housing beyond the shoulders I2. The sectional metal bushings is are then slipped into place in the annular members and the housing is drawn up until the shoulders are locked to the annular portions. The return bend is then inserted as clearly seen in dotted lines in Fig.l and swung into the The set screws 8 are then tightened up and this serves to press the face of the return bend tightly against the ends of the tubes forming a leakproot joint.

In the drawings I have shown the annular members l and 5 connected by an integral web or wall II. It may, however, in some cases be found desirable to cut this wall M in two and join it together by any of the well known means for uniting two separate parts so that when united they are to all intents and purposes the same as a single piece and I do not desire to be limited in this respect to the exact construction shown in the drawings.

It will be apparent that when the U bend is removed after loosening the set screws l .that access can be had to the interior of the tubes for the purpose of inserting tube cleaners; also that there is no possibility of the end of the tubes springing out of place due to the warping of the tubes inside the still as the housing holds the ends in alinement at all times.

Having described my invention what I regard as new and desire to secure by Letters Patent is:

1. In a refinery apparatus, a conventional return bend adapted to connect a pair of shouldered still tubes so as to provide a passageway therethrough, said tubes being demountably mounted in a housing for said return bend, said housing having annular portions, upwardly extending arcuate side walls integral with said annular portions and having integral connecting walls at their top, which form an inverted U, screws mounted in said connecting portions of the U, said connecting portions being spaced from the annular portions a. suilicient distance whereby when the set screws are raised the return bend can be inserted and removed from inside the housing, the inner ends of said set screws abutting the return bend to force it against the ends 01' the tubes to form a leak-proof joint.

2. In a refinery apparatus, a conventional return bend adapted to connect a pair of shouldered still tubes so as to provide a passageway therethrough, a housing for said return bend having annular portions, upwardly extending arcuate side walls integral with said annular portions and having integral connecting walls at their top, said tubes being demountablymounted in said housing, set screws mounted in said connecting walls, said connecting walls being spaced from each other and from the annular portions a sumcient distance whereby when the set screws are raised the return bend can be inserted and removed from inside the housing, the inner ends of said set screws abutting the return bend to force it against the ends of the tubes to form a leak-proof joint.

CHARLES E. ARD. 

